摘要：In this study, the United States Salinity Laboratory diagram has been convert to the continuous form and then the concentration values of Electrical Conductivity (EC) and Sodium Adsorption Ratio (SAR) combined together by a Fuzzy Inference System (FIS). Finally, ground water quality of Sirjan plain aquifer in Iran has been classified for irrigation purpose by proposed methods. Results obtained from FIS showed 84% general agreement with the results from the USSL diagram evaluation. Results showed that water quality classification with proposed method is more precise in comparison with USSL diagram classification and it improved error effects in hydro chemical experiments.
